|Publication number||US4359490 A|
|Application number||US 06/282,768|
|Publication date||Nov 16, 1982|
|Filing date||Jul 13, 1981|
|Priority date||Jul 13, 1981|
|Also published as||CA1187351A, CA1187351A1, DE3268385D1, EP0070751A1, EP0070751B1|
|Publication number||06282768, 282768, US 4359490 A, US 4359490A, US-A-4359490, US4359490 A, US4359490A|
|Inventors||William I. Lehrer|
|Original Assignee||Fairchild Camera & Instrument Corp.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Non-Patent Citations (1), Referenced by (70), Classifications (13), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to deposition of metal silicides and particularly to a low pressure chemical vapor deposition (LPCVD) process for co-depositing metal and silicon to form metal silicide on a surface such as, for example, a semi-conductor integrated circuit.
Metal silicides have attracted increasing attention recently as possible interconnect material for semiconductor integrated circuits. In particular, bilayer composite films of metal silicide and polycrystalline silicon have been found to provide low resistance gate and interconnect layers for MOS circuits and to be otherwise compatible with current silicon gate technology.
Tungsten disilicide has received particular attention as a candidate for such applications because its electrical resistivity is among the lowest of the metal silicides. In addition, tungsten disilicide grows a passivating silicon oxide layer if a silicon source is available and it is not attacked by HF solutions. Films of tungsten disilicide have been formed by sintering films of tungsten metal deposited on silicon by evaporation, sputtering, or chemical vapor deposition (CVD). They have also been formed by sintering mixed films of tungsten and silicon formed by co-evaporation, co-sputtering, or sputtering from a tungsten disilicide target.
In the fabrication of semiconductor integrated circuits, CVD methods are often preferred to physical deposition processes because CVD metal silicide films usually show more even step coverage than sputtered or evaporated film and the costs can be lower. In addition, CVD methods are production oriented and can result in purer films.
A basic problem, however, in depositing metal silicides by CVD methods is that it is sometimes difficult to deposit the metal component at the temperatures required for safe semiconductor device fabrication. For example, typical deposition temperatures for tantalum or titanium are over 1000° C., a temperature at which the junctions of a semi-conductor integrated circuit become damaged. A convenient temperature for deposition of metal silicides would be about 600°-650° C.
The present invention provides a low temperature process for depositing metal silicide, in situ, by the co-deposition of metal and silicon utilizing low pressure chemical vapor deposition techniques.
According to the process, a LPCVD reactor which is maintained at about 500°-700° C. and which contains a surface, such as the surface of a semiconductor integrated circuit, upon which metal silicide is to be deposited is first purged to remove oxidizing species. The initial purge comprises the successive steps of introducing an inert gas into the reactor, introducing a reducing atmosphere into the reactor, and introducing hydrogen chloride gas into the reactor. Next, silane is introduced into the reactor such that a base of polysilicon is deposited on the surface. Then, as silane introduction continues, a metal chloride vapor is introduced into the reactor such that metal and silicon are co-deposited on the polysilicon base as metal silicide. Following the co-deposition step, the reactor is purged by introducing a reducing atmosphere into the reactor. Finally, a neutral or inert gas is introduced into the reactor.
The thickness of the metal silicide deposition on the surface depends on the length of time that silane and metal chloride are simultaneously introduced into the reactor, the concentrations of silane and metal chloride and the temperature within the reactor.
The process of the present invention is generally applicable to the co:deposition of metal and silicon to form metal silicide on a surface wherein the metal is selected from the group consisting of tungsten, molybdenum, tantalum and niobium. However, the process will be described below using the co-deposition of tantalum and silicon to form tantalum silicide on the surface of a semiconductor integrated circuit as an example.
A conventional low pressure chemical vapor deposition reactor which contains a semiconductor integrated circuit is maintained at a temperature of about 500° C.-700° C., preferably about 600° C.-650° C. In a preferred embodiment of the invention, the reactor temperature profile is 610° C. at the front end of the reactor to 630° C. at the back end of the reactor.
Prior to the introduction of any process gases to the reactor, reactor pressure is reduced, typically to the base pressure of the LPCVD system. In the preferred embodiment, the pressure within the reactor is maintained at about 0.1-0.3 torr.
After the desired temperature and pressure conditions have been established, conventional initial CVD purging steps are utilized to clean the interior of the reactor. Reactor cleanliness is critical to successful deposition of metal silicide. First, an inert gas, preferably argon or nitrogen, is introduced into the reactor. This is followed by the introduction into the reactor of a reducing atmosphere, preferably hydrogen gas. Introduction of a reducing atmosphere is then followed by introduction of hydrogen chloride gas. According to the preferred embodiment, the hydrogen chloride gas is introduced such that it etches contaminants from the surface of the semiconductor integrated circuit upon which metal silicide is to be deposited to produce an atomically clean surface.
After the initial purge of the reactor has been completed, silane is introduced into the reactor such that a base layer of polysilicon is deposited upon the surface of the semiconductor integrated circuit. Preferably, silane is introduced at a rate sufficient to maintain a reactor pressure of about 0.3 torr. Those skilled in the art will appreciate that this rate will depend upon the geometry of the specific reactor utilized.
Next, tantalum and silicon are simultaneously co-deposited to form a layer of tantalum silicide on the polysilicon base. Co-deposition of tantalum and silicon to form tantalum silicide is accomplished by maintaining silane flow while simultaneously introducing tantalum chloride vapor to the reactor. Silane is introduced at a rate sufficient to maintain a partial pressure of about 0.2 torr. The tantalum chloride vapor is introduced at a rate sufficient to maintain the total pressure at about 0.275 torr. In the preferred embodiment, the tantalum chloride vapor is introduced into the reactor using hydrogen as a carrier gas (In the case where another metal selected from the group listed above is used, the carrier gas may be hydrogen or may not be required.). The thickness of the tantalum silicide layer deposited on the polysilicon base depends on the length of time that silane and tantalum chloride are simultaneously introduced to the reactor as well as on the concentrations of silane and tantalum chloride and the temperature within the reactor.
The tantalum chloride gas is generated from solid tantalum chloride, typically a powder, contained in a saturator contained inside an oven maintained at about 100°-175° C. Also within the oven are heat exchangers which preheat the hydrogen carrier gas prior to its pass through the saturator. The heated hydrogen carrier gas is then mixed with the source gas containing tantalum chloride. The lines leading from the source oven to the reactor are maintained at about 50° C. above the temperature of the oven to avoid condensation of the tantalum chloride.
Tantalum silicide is deposited on the surface of the semiconductor device at a rate of about 100-300 Angstroms per minute. The lower the rate, the greater the accuracy of deposition. A preferred deposition rate is about 100-200 Angstroms per minute.
Following the deposition of tantalum silicide, the reactor is again purged. First, a reducing atmosphere, preferably hydrogen gas, is introduced into the reactor for about ten minutes at a pressure of about 0.3 torr. Finally, an inert atmosphere, preferably argon or nitrogen gas, is introduced into the reactor for about ten minutes at a pressure of about 10 torr.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3381182 *||Oct 19, 1964||Apr 30, 1968||Philco Ford Corp||Microcircuits having buried conductive layers|
|US3540920 *||Aug 24, 1967||Nov 17, 1970||Texas Instruments Inc||Process of simultaneously vapor depositing silicides of chromium and titanium|
|US3881242 *||Nov 8, 1973||May 6, 1975||Ferranti Ltd||Methods of manufacturing semiconductor devices|
|US4180596 *||Jun 30, 1977||Dec 25, 1979||International Business Machines Corporation||Method for providing a metal silicide layer on a substrate|
|US4276557 *||Dec 29, 1978||Jun 30, 1981||Bell Telephone Laboratories, Incorporated||Integrated semiconductor circuit structure and method for making it|
|1||*||Kern, "Advances in Deposition Processes for Passivation Films", J. Vac. Sci. Technol, vol. 14, No. 5, Sep./Oct. 1977, pp. 1082-1099.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4419385 *||Sep 24, 1981||Dec 6, 1983||Hughes Aircraft Company||Low temperature process for depositing an oxide dielectric layer on a conductive surface and multilayer structures formed thereby|
|US4501769 *||Feb 9, 1983||Feb 26, 1985||Siemens Aktiengesellschaft||Method for selective deposition of layer structures consisting of silicides of HMP metals on silicon substrates and products so-formed|
|US4504521 *||Mar 22, 1984||Mar 12, 1985||Rca Corporation||LPCVD Deposition of tantalum silicide|
|US4510670 *||Jan 17, 1983||Apr 16, 1985||Siemens Aktiengesellschaft||Method for the manufacture of integrated MOS-field effect transistor circuits silicon gate technology having diffusion zones coated with silicide as low-impedance printed conductors|
|US4557943 *||Oct 31, 1983||Dec 10, 1985||Advanced Semiconductor Materials America, Inc.||Metal-silicide deposition using plasma-enhanced chemical vapor deposition|
|US4608271 *||Mar 22, 1985||Aug 26, 1986||Siemens Aktiengesellschaft||Method for the manufacture of metal silicide layers by means of reduced pressure gas phase deposition|
|US4619038 *||Aug 15, 1985||Oct 28, 1986||Motorola, Inc.||Selective titanium silicide formation|
|US4668530 *||Jul 23, 1985||May 26, 1987||Massachusetts Institute Of Technology||Low pressure chemical vapor deposition of refractory metal silicides|
|US4684542 *||Aug 11, 1986||Aug 4, 1987||International Business Machines Corporation||Low pressure chemical vapor deposition of tungsten silicide|
|US4709655 *||Dec 3, 1985||Dec 1, 1987||Varian Associates, Inc.||Chemical vapor deposition apparatus|
|US4766006 *||May 15, 1986||Aug 23, 1988||Varian Associates, Inc.||Low pressure chemical vapor deposition of metal silicide|
|US4796562 *||Jan 15, 1987||Jan 10, 1989||Varian Associates, Inc.||Rapid thermal cvd apparatus|
|US4800105 *||Jul 17, 1987||Jan 24, 1989||Nihon Shinku Gijutsu Kabushiki Kaisha||Method of forming a thin film by chemical vapor deposition|
|US4814294 *||Jul 30, 1987||Mar 21, 1989||Allied-Signal Inc.||Method of growing cobalt silicide films by chemical vapor deposition|
|US4816643 *||Mar 9, 1987||Mar 28, 1989||Allied-Signal Inc.||Glow plug having a metal silicide resistive film heater|
|US4822636 *||Dec 16, 1986||Apr 18, 1989||Canon Kabushiki Kaisha||Method for forming deposited film|
|US4834023 *||Dec 19, 1986||May 30, 1989||Canon Kabushiki Kaisha||Apparatus for forming deposited film|
|US4837048 *||Oct 17, 1986||Jun 6, 1989||Canon Kabushiki Kaisha||Method for forming a deposited film|
|US4844950 *||Dec 16, 1986||Jul 4, 1989||Canon Kabushiki Kaisha||Method for forming a metal film on a substrate|
|US4849249 *||Apr 25, 1988||Jul 18, 1989||Canon Kabushiki Kaisha||Deposited film forming process and deposited film forming device|
|US4861623 *||Dec 16, 1986||Aug 29, 1989||Canon Kabushiki Kaisha||Method for forming deposited film by generating precursor with halogenic oxidizing agent|
|US4865883 *||Jan 17, 1989||Sep 12, 1989||Canon Kabushiki Kaisha||Method for forming a deposited film containing IN or SN|
|US4869931 *||Jan 17, 1989||Sep 26, 1989||Canon Kabushiki Kaisha||Method for forming deposited films of group II-VI compounds|
|US4885258 *||Nov 1, 1988||Dec 5, 1989||Canon Kabushiki Kaisha||Method for making a thin film transistor using a concentric inlet feeding system|
|US4904620 *||Apr 4, 1988||Feb 27, 1990||U.S. Philips Corporation||Method of manufacturing a semiconductor device including a titanium disilicide contact|
|US4915988 *||Jun 22, 1988||Apr 10, 1990||Georgia Tech Research Corporation||Chemical vapor deposition of group IIA metals and precursors therefor|
|US4957777 *||Oct 12, 1989||Sep 18, 1990||Massachusetts Institute Of Technology||Very low pressure chemical vapor deposition process for deposition of titanium silicide films|
|US4968644 *||May 5, 1988||Nov 6, 1990||At&T Bell Laboratories||Method for fabricating devices and devices formed thereby|
|US4992305 *||Jun 22, 1988||Feb 12, 1991||Georgia Tech Research Corporation||Chemical vapor deposition of transistion metals|
|US5160543 *||Feb 21, 1992||Nov 3, 1992||Canon Kabushiki Kaisha||Device for forming a deposited film|
|US5300322 *||Mar 10, 1992||Apr 5, 1994||Martin Marietta Energy Systems, Inc.||Molybdenum enhanced low-temperature deposition of crystalline silicon nitride|
|US5629114 *||Jun 7, 1995||May 13, 1997||Ulvac Coating Corporation||Phase shift mask and manufacturing method thereof and exposure method using phase shift mask comprising a semitransparent region|
|US5674647 *||Oct 24, 1995||Oct 7, 1997||Ulvac Coating Corporation||Phase shift mask and manufacturing method thereof and exposure method using phase shift mask|
|US5691090 *||Dec 20, 1996||Nov 25, 1997||Ulvac Coating Corporation||Phase shift mask and manufacturing method thereof and exposure method using phase shift mask|
|US5830607 *||May 27, 1997||Nov 3, 1998||Ulvac Coating Corporation||Phase shift mask and manufacturing method thereof and exposure method using phase shift mask|
|US5851871 *||Jul 3, 1996||Dec 22, 1998||Sgs-Thomson Microelectronics, S.R.L.||Process for manufacturing integrated capacitors in MOS technology|
|US6096630 *||Oct 14, 1997||Aug 1, 2000||Lg Semicon Co., Ltd.||Method for fabricating semiconductor device|
|US6143362 *||Feb 25, 1998||Nov 7, 2000||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US6171943||Aug 19, 1999||Jan 9, 2001||Micron, Technology, Inc.||Methods of forming a contact having titanium silicide formed by chemical vapor deposition|
|US6208033||Aug 19, 1999||Mar 27, 2001||Micron Technology Inc.||Apparatus having titanium silicide and titanium formed by chemical vapor deposition|
|US6221762||Oct 14, 1997||Apr 24, 2001||Hyundai Electronics Industries Co., Ltd.||Method for fabricating semiconductor device having improved step coverage and low resistivity contacts|
|US6251777||Mar 5, 1999||Jun 26, 2001||Taiwan Semiconductor Manufacturing Company||Thermal annealing method for forming metal silicide layer|
|US6255209||Aug 19, 1999||Jul 3, 2001||Micron Technology, Inc.||Methods of forming a contact having titanium formed by chemical vapor deposition|
|US6255216||Aug 19, 1999||Jul 3, 2001||Micron Technology, Inc.||Methods of forming a contact having titanium silicide and titanium formed by chemical vapor deposition|
|US6284316||Jan 20, 2000||Sep 4, 2001||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US6433434||Sep 3, 1999||Aug 13, 2002||Micron Technology, Inc.||Apparatus having a titanium alloy layer|
|US6472756||Feb 21, 2001||Oct 29, 2002||Micron Technology, Inc.||Method of forming titanium silicide and titanium by chemical vapor deposition and resulting apparatus|
|US6830820||Aug 28, 2001||Dec 14, 2004||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US6830838||Aug 28, 2001||Dec 14, 2004||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US6878627 *||Aug 13, 2003||Apr 12, 2005||United Microelectronics Corporation||Semiconductor device with cobalt silicide contacts and method of making the same|
|US6903462||Aug 28, 2001||Jun 7, 2005||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US6940172||Aug 28, 2001||Sep 6, 2005||Micron Technology, Inc.||Chemical vapor deposition of titanium|
|US7443032||Jun 7, 2005||Oct 28, 2008||Micron Technology, Inc.||Memory device with chemical vapor deposition of titanium for titanium silicide contacts|
|US8235305||Apr 20, 2010||Aug 7, 2012||Ae Polysilicon Corporation||Methods and system for cooling a reaction effluent gas|
|US8425855||Apr 20, 2010||Apr 23, 2013||Robert Froehlich||Reactor with silicide-coated metal surfaces|
|US8456007||Jun 4, 2013||Round Rock Research, Llc||Chemical vapor deposition of titanium|
|US20050176248 *||Apr 8, 2005||Aug 11, 2005||Water Lur||Semiconductor device with cobalt silicide contacts|
|US20050179139 *||Apr 8, 2005||Aug 18, 2005||Water Lur||Semiconductor device with cobalt silicide contacts|
|US20050255698 *||Jun 7, 2005||Nov 17, 2005||Micron Technology, Inc.||Chemical vapor deposition of titanim|
|US20060014388 *||Sep 12, 2005||Jan 19, 2006||Water Lur||Wafer processing apparatus & methods for depositing cobalt silicide|
|US20100263734 *||Apr 20, 2010||Oct 21, 2010||Robert Froehlich||Methods and system for cooling a reaction effluent gas|
|US20100266466 *||Oct 21, 2010||Robert Froehlich||Reactor with silicide-coated metal surfaces|
|US20100266762 *||Oct 21, 2010||Ben Fieselmann||Processes and an apparatus for manufacturing high purity polysilicon|
|US20100273010 *||Mar 19, 2010||Oct 28, 2010||Robert Froehlich||Silicide-coated metal surfaces and methods of utilizing same|
|US20150044842 *||Aug 9, 2013||Feb 12, 2015||Taiwan Semiconductor Manufacturing Company, Ltd.||Integrating Junction Formation of Transistors with Contact Formation|
|DE3413064A1 *||Apr 6, 1984||Oct 31, 1985||Siemens Ag||Verfahren zum herstellen von metallsilizidschichten durch abscheidung aus der gasphase bei vermindertem druck und deren verwendung|
|DE3908676A1 *||Mar 16, 1989||Jun 28, 1990||Samsung Electronics Co Ltd||Process for forming low-resistance contacts on at least two n<+>-/p<+>-type pre-ohmic zones of a large-scale integrated semiconductor circuit|
|EP0245934A2 *||Mar 27, 1987||Nov 19, 1987||Varian Associates, Inc.||Low pressure chemical vapor deposition of metal silicide|
|WO1990010098A1 *||Feb 23, 1990||Sep 7, 1990||Interuniversitair Micro-Elektronica Centrum Vzw||A method and an apparatus for disposing epitaxial silicon and silicides|
|WO2010123873A1 *||Apr 20, 2010||Oct 28, 2010||Ae Polysilicon Corporation||A reactor with silicide-coated metal surfaces|
|U.S. Classification||438/680, 257/E21.2, 438/683, 427/255.28, 427/96.8, 438/905, 427/126.1|
|International Classification||H01L21/205, H01L21/28, H01L21/285|
|Cooperative Classification||Y10S438/905, H01L21/28061|
|Jul 13, 1981||AS||Assignment|
Owner name: FAIRCHILD CAMERA AND INSTRUMENT CORPORATION, 464 E
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:LEHRER, WILLIAM I.;REEL/FRAME:003900/0781
Effective date: 19810709
|Apr 11, 1986||FPAY||Fee payment|
Year of fee payment: 4
|Jan 8, 1990||FPAY||Fee payment|
Year of fee payment: 8
|Apr 27, 1994||FPAY||Fee payment|
Year of fee payment: 12
|Aug 5, 1996||AS||Assignment|
Owner name: NATIONAL SEMICONDUCTOR CORPORATION, CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FAIRCHILD SEMICONDUCTOR CORPORATION;REEL/FRAME:008059/0846
Effective date: 19960726